In recent years, light sources such as light-emitting diodes (LEDs) have been improved through technological advances in material and manufacturing processes. An LED possesses relatively high efficiency, long life, and vivid colors, and can be used in a variety of industries including the automotive, computer, telecom, military and consumer goods industries, etc. One example is an LED lamp which uses LEDs to replace traditional light sources such as electrical filaments.
There are some conventional ways to regulate the light sources. For example, a power converter receives an AC voltage from a power source, and generates a DC voltage to power the LED light source. A controller regulates an output of the power converter according to a dimmer coupled between the AC power source and the power converter to regulate the brightness of the LED light source. Conventional dimmers include TRIAC (Triode Alternating Current) dimmers and ON/OFF dimmers. However, these dimmers can only adjust the brightness of the light sources but cannot adjust the color temperature of the light sources.